Commit Graph

19 Commits

Author SHA1 Message Date
Paul E. McKenney
e15aed426a doc: Update checklist.rst discussion of callback execution
This commit completes the list of call_rcu*() functions that are not
guaranteed to have their callbacks executing on the same CPU.  While in
the area, fix an unrelated typo.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2024-02-14 07:53:50 -08:00
Paul E. McKenney
739337d482 doc: Add CONFIG_RCU_STRICT_GRACE_PERIOD to checklist.rst
This commit adds CONFIG_RCU_STRICT_GRACE_PERIOD to the list of debugging
Kconfig options in checklist.rst.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2024-02-14 07:53:49 -08:00
Paul E. McKenney
3cf5016121 doc: Make checklist.rst note that spinlocks are implied RCU readers
In kernels built with CONFIG_PREEMPT_RT=n, spinlock critical sections
are RCU readers because they disable preemption.  However, they are also
RCU readers in CONFIG_PREEMPT_RT=y because in that case the locking
primitives contain rcu_read_lock() and rcu_read_unlock().  Therefore,
upgrade checklist.rst to document this non-obvious case.

While in the area, fix a typo by changing "read-side critical" to
"read-side critical section".

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2024-02-14 07:53:49 -08:00
Paul E. McKenney
1b7178b23d doc: Clarify RCU Tasks reader/updater checklist
Currently, the reader/updater compatibility rules for the three RCU
Tasks flavors are squished together in a single paragraph, which can
result in confusion.  This commit therefore splits them out into a list,
clearly showing the distinction between these flavors.

Link: https://lore.kernel.org/all/20231002211936.5948253e@gandalf.local.home/

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
2023-12-14 01:15:52 +05:30
Qiuxu Zhuo
e5ad8b68f8 Documentation/RCU: s/not/note/ in checklist.rst
"Please not that you *cannot* rely..." has a typo.
Fix it.

Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
2023-04-05 13:47:18 +00:00
Paul E. McKenney
3e7768b7ad doc: Update checklist.txt
This commit updates checklist.txt to reflect RCU additions and changes
over the past few years.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-10-18 14:58:50 -07:00
Linus Torvalds
f3dfe925f9 There's not a huge amount of activity in the docs tree this time around,
but a few significant changes even so:
 
 - A complete rewriting of the top-level index.rst file, which mostly
   reflects itself in a redone top page in the HTML-rendered docs.  The hope
   is that the new organization will be a friendlier starting point for
   both users and developers.
 
 - Some math-rendering improvements.
 
 - A coding-style.rst update on the use of BUG() and WARN()
 
 - A big maintainer-PHP guide update.
 
 - Some code-of-conduct updates
 
 - More Chinese translation work
 
 Plus the usual pile of typo fixes, corrections, and updates.
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Merge tag 'docs-6.1' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "There's not a huge amount of activity in the docs tree this time
  around, but a few significant changes even so:

   - A complete rewriting of the top-level index.rst file, which mostly
     reflects itself in a redone top page in the HTML-rendered docs. The
     hope is that the new organization will be a friendlier starting
     point for both users and developers.

   - Some math-rendering improvements.

   - A coding-style.rst update on the use of BUG() and WARN()

   - A big maintainer-PHP guide update.

   - Some code-of-conduct updates

   - More Chinese translation work

  Plus the usual pile of typo fixes, corrections, and updates"

* tag 'docs-6.1' of git://git.lwn.net/linux: (66 commits)
  checkpatch: warn on usage of VM_BUG_ON() and other BUG variants
  coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel")
  Documentation: devres: add missing IO helper
  Documentation: devres: update IRQ helper
  Documentation/mm: modify page_referenced to folio_referenced
  Documentation/CoC: Reflect current CoC interpretation and practices
  docs/doc-guide: Add documentation on SPHINX_IMGMATH
  docs: process/5.Posting.rst: clarify use of Reported-by: tag
  docs, kprobes: Fix the wrong location of Kprobes
  docs: add a man-pages link to the front page
  docs: put atomic*.txt and memory-barriers.txt into the core-api book
  docs: move asm-annotations.rst into core-api
  docs: remove some index.rst cruft
  docs: reconfigure the HTML left column
  docs: Rewrite the front page
  docs: promote the title of process/index.rst
  Documentation: devres: add missing SPI helper
  Documentation: devres: add missing PINCTRL helpers
  docs: hugetlbpage.rst: fix a typo of hugepage size
  docs/zh_CN: Add new translation of admin-guide/bootconfig.rst
  ...
2022-10-03 10:23:32 -07:00
Akhil Raj
7f77ebbf75 Delete duplicate words from kernel docs
I have deleted duplicate words like

to, guest, trace, when, we

Signed-off-by: Akhil Raj <lf32.dev@gmail.com>
Link: https://lore.kernel.org/r/20220829065239.4531-1-lf32.dev@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-09-27 13:21:43 -06:00
Paul E. McKenney
1c1c1d983e doc: Use rcu_barrier() to rate-limit RCU callbacks
The checklist.rst document advises periodic synchronize_rcu() invocations
to prevent callback flooding.  However, rcu_barrier() is often a better
choice.  This commit therefore adds words to this effect.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31 04:58:15 -07:00
Paul E. McKenney
ed336c6fe4 doc: Call out queue_rcu_work() for blocking RCU callbacks
The current checklist.rst file correctly notes that RCU callbacks execute
in BH context, and cannot block.  This commit adds words advising people
needing callbacks to block to use workqueues, for example, by replacing
call_rcu() with queue_rcu_work().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31 04:58:14 -07:00
Paul E. McKenney
4d2f862b5b doc: Emphasize the need for explicit RCU read-side markers
This commit updates checklist.rst to emphasize the need for explicit
markers for RCU read-side critical sections.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31 04:58:14 -07:00
Akira Yokosawa
404147faaa docs: Update RCU cross-references as suggested in doc-guide
The RCU documentation contains old-style cross references which
do not follow the best practices outlined in doc-guide/sphinx.rst.
In addition, some of the cross references use URLs that should be replaced
by pathnames.

Update all of these cross references and adjust the surrounding words.

Summary of changes:

  - out-of-date plaintext file names (*.txt) -> *.rst
  - references by :ref: tags -> path names of *.rst
    * use relative paths to .rst files under the RCU/ subdirectory
    * use abs paths of Documentation/xxx for other .rst files
  - references by URL under https://www.kernel.org/ -> paths of *.rst
  - adjust surrounding words of some of updated references.

Note:
  The automarkup.py script interprets references via "*.txt" as if they
were via "*.rst", so the *.txt -> *.rst changes should be regarded as
cleanups rather than bug fixes.

Cc: rcu@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:13:52 -07:00
Akira Yokosawa
e3879ecd36 Documentation/RCU: Fix emphasis markers
"-foo-" does not work as emphasis in ReST markdown.
Use "*foo*" instead.

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-07-20 13:36:33 -07:00
Toke Høiland-Jørgensen
e74c74f9e5 doc: Give XDP as example of non-obvious RCU reader/updater pairing
This commit gives an example of non-obvious RCU reader/updater pairing
in the guise of the XDP feature in networking, which calls BPF programs
from network-driver NAPI (softirq) context.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210624160609.292325-4-toke@redhat.com
2021-06-24 19:41:14 +02:00
Paul E. McKenney
9a145c04a2 doc: Clarify and expand RCU updaters and corresponding readers
This commit clarifies which primitives readers can use given that the
corresponding updaters have made a specific choice.  This commit also adds
this information for the various RCU Tasks flavors.  While in the area, it
removes a paragraph that no longer applies in any straightforward manner.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210624160609.292325-3-toke@redhat.com
2021-06-24 19:41:14 +02:00
Sebastian Andrzej Siewior
81ad58be2f doc: Use CONFIG_PREEMPTION
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Update the documents and mention CONFIG_PREEMPTION. Spell out
CONFIG_PREEMPT_RT (instead PREEMPT_RT) since it is an option now.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-01-06 16:10:44 -08:00
Paul Gortmaker
9d3a04853f docs: Fix typos and drop/fix dead links in RCU documentation
It appears the Compaq link moved to a machine at HP for a while
after the merger of the two, but that doesn't work either.  A search
of HP for "wiz_2637" (w and w/o html suffix) comes up empty.

Since the references aren't critical to the documents we remove them.

Also, the lkml.kernel.org/g links have been broken for ages, so replace
them with lore.kernel.org/r links - standardize on lore for all links too.

Note that we put off fixing these 4y ago - presumably thinking that a
treewide fixup was pending.  Probably safe to go fix the RCU ones now.

https://lore.kernel.org/r/20160915144926.GD10850@linux.vnet.ibm.com/

Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-01-04 13:35:14 -08:00
Paul E. McKenney
86b5a7381b doc: Present the role of READ_ONCE()
This commit adds an explanation of the special cases where READ_ONCE()
may be used in place of a member of the rcu_dereference() family.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-11-02 17:07:15 -08:00
Mauro Carvalho Chehab
6b05dfacd7 docs: RCU: Convert checklist.txt to ReST
- Add a SPDX header;
- Adjust document title;
- Some whitespace fixes and new line breaks;
- Use the right list markups;
- Add it to RCU/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-29 11:58:10 -07:00